Trust no one, p2pool it is for me then.
That's not to say that there aren't any trustworthy pools out there, there are, but IMHO there's not so many truly trustworthy pools to choose from out of the many available - with more springing up every week it seems. I spent weeks combing through this & other forums looking at different pools trying to decide what pool I felt comfortable using, & came to the same conclusion as you - p2pool seemed to be not only the safest, but also the decentralized nature of it appealed to me.
Although stealing hashrate is a grey area, I did find a case where a certain pool admin used their miners hash power to kill a coin by way of a 51% attack simply because he didn't like it. This was done without any consultation with the pools miners & without their knowing - which of course meant that that pool was immediately crossed of my list, you can read about it here:
https://bitcointalk.org/index.php?topic=56675.0https://bitcoin.stackexchange.com/questions/3472/what-is-the-story-behind-the-attack-on-coiledcoinThen of course there's the double spending attack done by another (very large at the time) pool:
https://bitcointalk.org/index.php?topic=327767.0To me, the two examples above
could be considered stealing, weather directly or indirectly. At the end of the day, if you're concerned about weather a pool will "steal" your hashing power it's safer & easier to use either p2pool or one of the very few reputable pools out there that provide not only open & transparent support, but do so in a timely manner. Doing plenty of pool research will pay dividends, I'm certainly glad I took the time to do so. One thing's for sure, biggest is by no means best.